The spinal column is made up of many parts, all designed to help the back move flexibly, support body weight and protect the spinal cord and nerves. These parts include the:. Skip to content. Anatomy of the Spine Not what you're looking for? Start New Search. About anatomy of the spine The human spine is a complex anatomic structure that is the scaffolding for the entire body. It provides several important functions, including: Protecting the spinal cord and nerves Structural support for the body, allowing us to stand upright.
The spine supports about half the weight of the body. The spine above the sacrum consists of: Seven bones in the neck—the cervical spine 12 bones in the chest—the thoracic spine Five bones in the lower back—the lumbar spine The spinal column combines strong bones, unique joints, flexible ligaments and tendons, large muscles and highly sensitive nerves.
Some causes of spinal pain include: Irritation of the large nerves as they exit the bony confines of the spine leading to the arms and legs Irritation of the smaller nerves of the spine that involve innervate or supply the discs between the vertebrae, facets and ligaments Strain of the large muscles of the back that hold the spine upright Injuries to the bones, ligaments or joints Damage or disease to the discs that separate the vertebrae Abnormal movement between segments Tumors, infection, trauma, deformity or other spinal disorders The spinal column is made up of many parts, all designed to help the back move flexibly, support body weight and protect the spinal cord and nerves.
All rights reserved. This information is not intended as a substitute for professional medical care. Symptoms of cauda equina syndrome include:. The symptoms of cauda equina syndrome require immediate medical attention.
You should seek out emergency medical attention for one or more of the symptoms of this condition. If you have cauda equina syndrome, you will need surgery to relieve pressure off of the nerves, and the best outcomes are with 48 hours of the start of symptoms. There are treatments for sacral vertebrae injuries.
Sacral injuries can also affect the tailbone. This type of injury—called coccydynia—is likely to cause bruising, discoloration, or fracture of the tailbone. Home treatment of sacral and tailbone injuries might be all a person needs. However, if these fractures are severe or affect nerves, surgery might be necessary. It is important to remember that bones heal best when a person takes good care of themselves in a variety of helpful ways, including eating right and not smoking. Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life.
Cartilage formation in the pelvic skeleton during the embryonic and early-fetal period. PLoS One. Neural innervation patterns in the sacral vertebral body. Eur Spine J. Imaging and treatment of sacral insufficiency fractures. American Journal of Neuroradiology. February ;31 2 Cleveland Clinic. Stress Fractures. Updated June 17, Anatomy, back, cauda equina.
Updated December 6, American Association of Neurological Surgeons. Anatomy of the Spine and Peripheral Nervous System. Medline Plus. Tailbone trauma — aftercare. Updated October 11, Your Privacy Rights. To change or withdraw your consent choices for VerywellHealth. At any time, you can update your settings through the "EU Privacy" link at the bottom of any page.
These choices will be signaled globally to our partners and will not affect browsing data. We and our partners process data to: Actively scan device characteristics for identification. The back muscles stabilize your spine. Something as common as poor muscle tone or a large belly can pull your entire body out of alignment. Misalignment puts incredible strain on the spine see Exercise for a Healthy Back. Vertebrae are the 33 individual bones that interlock with each other to form the spinal column.
The vertebrae are numbered and divided into regions: cervical, thoracic, lumbar, sacrum, and coccyx Fig. Only the top 24 bones are moveable; the vertebrae of the sacrum and coccyx are fused. The vertebrae in each region have unique features that help them perform their main functions.
Cervical neck - the main function of the cervical spine is to support the weight of the head about 10 pounds. The seven cervical vertebrae are numbered C1 to C7.
The neck has the greatest range of motion because of two specialized vertebrae that connect to the skull. The first vertebra C1 is the ring-shaped atlas that connects directly to the skull. The second vertebra C2 is the peg-shaped axis, which has a projection called the odontoid, that the atlas pivots around. Thoracic mid back - the main function of the thoracic spine is to hold the rib cage and protect the heart and lungs. The twelve thoracic vertebrae are numbered T1 to T The range of motion in the thoracic spine is limited.
Lumbar low back - the main function of the lumbar spine is to bear the weight of the body. The five lumbar vertebrae are numbered L1 to L5. These vertebrae are much larger in size to absorb the stress of lifting and carrying heavy objects. Sacrum - the main function of the sacrum is to connect the spine to the hip bones iliac. There are five sacral vertebrae, which are fused together. Together with the iliac bones, they form a ring called the pelvic girdle.
Coccyx region - the four fused bones of the coccyx or tailbone provide attachment for ligaments and muscles of the pelvic floor. While vertebrae have unique regional features, every vertebra has three functional parts Fig. Each vertebra in your spine is separated and cushioned by an intervertebral disc, which keeps the bones from rubbing together. Discs are designed like a radial car tire.
The outer ring, called the annulus, has crisscrossing fibrous bands, much like a tire tread. These bands attach between the bodies of each vertebra. Inside the disc is a gel-filled center called the nucleus, much like a tire tube Fig. Discs function like coiled springs. The crisscrossing fibers of the annulus pull the vertebral bones together against the elastic resistance of the gel-filled nucleus. The nucleus acts like a ball bearing when you move, allowing the vertebral bodies to roll over the incompressible gel.
The gel-filled nucleus contains mostly fluid. This fluid is absorbed during the night as you lie down and is pushed out during the day as you move upright. With age, our discs increasingly lose the ability to reabsorb fluid and become brittle and flatter; this is why we get shorter as we grow older. Also diseases, such as osteoarthritis and osteoporosis, cause bone spurs osteophytes to grow.
Injury and strain can cause discs to bulge or herniate, a condition in which the nucleus is pushed out through the annulus to compress the nerve roots causing back pain. On the back of each vertebra are bony projections that form the vertebral arch.
The arch is made of two supporting pedicles and two laminae Fig.
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